The present invention relates generally to systems for filtering storm water run-off and specifically to drain inlets and structures for use in drain inlets to inhibit the flow of pollutants, debris and other contaminants into drainage systems.
Drainage systems for receiving fluid flow are well known in the art. Such systems provide a path for fluid flow from surface areas and often transport the fluid from surface areas directly to the ocean, rivers, lakes, estuaries, streams and the like without regard to the removal of debris, pollutants or other contaminants. For example, because of the Federal Environmental Protection Agency""s Clean Water Act, controlling pollution from storm water runoff is receiving ever-increasing attention at all levels of government, Federal, State and local. Federal and state agencies have issued mandates and developed guidelines regarding the prevention of non-point source (storm water caused) pollution that require local governments to act upon or initiate.
Because of the aforementioned mandates, many cities and special districts have developed plans and taken action to prevent storm water pollution. These actions range from those that are educational in nature (labeling storm water inlets with phrases such as xe2x80x9cNo dumpingxe2x80x94Flows into Rivers and Streamsxe2x80x9d) to active measures to remove pollutants. Such measures generally require the installation of equipment for removing contaminants somewhere between where the storm water enters the drainage system and the ultimate body of water receiving the runoff.
Several types of equipment are employed to reduce pollution and contaminants from storm water runoff. Catch basin filtration systems use devices installed at the point that the storm water enters the drainage system. The water flow is directed through an installed adsorbent material that aids in removing contaminants from the storm water while allowing the water to flow into the drainage system. Such a permanently installed catch basin filtration system is disclosed in U.S. Pat. No. 5,720,574. In addition to catch basin filtration systems, oil/water separators are employed. Such systems generally comprise large underground holding tanks that allow silt and pollutants to settle to the bottom of the tank and the water to flow into the drainage system. Other systems also exist to remove contaminants from water runoff. However, these systems are also generally permanent installations that are expensive to install and maintain.
As various maintainable catch basin filtration systems for filtering storm water runoff have been developed additional problems have evolved. An initial problem involves the installation of these systems in the wide variety of drain inlets and catch basins that currently exist. Drain inlets and catch basins have wide variances in dimensions, particularly in overall volume and distance across the mouth of the opening. Accordingly, fixed-dimension filtration systems are thus unable to account for variances in catch basin dimensions. Accordingly, catch basin filtration systems having varying dimensions are desired.
Moreover, because such filtration systems typically require regular maintenance, issues arise such as ease of access and the length of time that a system can operate between cleaning or replacing filter elements or other parts. Access to elements that must be cleaned or replaced is problematic in some systems, such that a heightened burden is placed on those who regularly maintain these systems. In addition, silt, sediment and other debris tend to settle on or around filter elements in many filtration systems, such that the length of time that these elements can effectively filter storm water runoff is significantly reduced. Therefore, catch basin filtration systems having improved accessibility for maintained parts and longer periods of effectively filtering storm water runoff before requiring maintenance are desired.
Another significant problem that has emerged in the development of catch basin filtration systems is the ability of such systems to process large quantities of fluid during peak flow periods without having backups or stoppages that result in localized flooding of surrounding areas. Peak flow periods would include, for example, extreme storm conditions or other flood type conditions. Due to concerns over storm drainage backups that can result in localized flooding, many filtration systems employ some form of a high-flow bypass feature that allows excess fluids to proceed through the drainage system without being filtered during periods of high fluid flow. As a result, these types of filtration systems have an upper limit for the amount of fluid that can be filtered at any given time as well as a maximum capacity for the amount of fluid that can be passed through the system in any event.
In practice, many catch basin filtration systems have proven to be inferior in one or both of these areas, with the result being that the filtering of storm water runoff is inadequate and/or that these systems become backed up and flood the surrounding local area. As some filtration systems have attempted to overcome these problems by increasing the volume of the fluid retaining trough or reservoir in the filtration system, these systems have encountered problems in maintaining the shape of the reservoir during periods of high flow. In these filtration systems, the reservoir tends to expand under the increased weight of the contained fluid, such that the expanded reservoir can fill the entire inner catch basin and partially or wholly block the high flow bypass and other fluid routes. This then results in a backed up drainage system and localized flooding. Accordingly, catch basin filtration systems having increased flow capacity for both filtered flows and high flow bypass flows are desired. In addition, it is desired that the fluid retaining reservoir in such systems substantially retain its overall shape during periods of high flow such that unwanted blockages and flooding are avoided.
In addition, the high flow bypass in many current filtration systems is effectively unable to restrain large objects or xe2x80x9cfloatables,xe2x80x9d such as cigarette butts, during high flow periods. These objects typically pass through the filtration and drainage systems unimpeded whenever the high flow bypass is utilized in these systems. Accordingly, catch basin filtration systems that inhibit or restrain large objects or floatables from passing through high flow bypass areas are desired.
The present invention is directed to a disposable or re-useable catch basin filtration system that is effective and economical to install and maintain. Generally, the apparatus comprises a filter body dimensioned to fit within an inlet and forming a trough obstructing at least a portion of the inlet. The filter body is supported by a filter body support dimensioned to cooperatively engage with the inlet and the filter body to substantially maintain the filter body in a pre-selected shape and position with the inlet. One or more connectors removably connect the filter body to the filter body support.
In one embodiment, the filter structure comprises a filter body made of a tough, permeable material, such as a woven geotextile material. The filter body forms a trough that is supported in a drain inlet by a supporting structure, such as a steel frame, to maintain the filter body in the desired shape for receiving fluid flow entering the drain inlet. The filter body allows fluid, such as water runoff, to pass through while inhibiting the flow of debris and sedimentation contained in the runoff through the filter body. In addition, one or more adsorbent containers can be placed in the filter body to remove pollutants or contaminants from fluid flowing through the filter body. For example, the adsorbent containers, such as a permeable pouch, may contain adsorbents for removing hydrocarbons from fluid flowing through the filter body.
In another embodiment, the filter body is supported in the inlet and forms a trough around the perimeter of the inside wall of the inlet. The interior wall of the trough forms a dam that is lower than the outer wall of the trough. Adsorbent pouches can be preferably removably attached, such as by velcro, to the outer wall and the dam of the trough. During periods of fluid flow, such as storm water runoff, the fluid flows into the inlet and enters the filter body. As the level of the water rises in the filter body, it causes the adsorbent pouches to float. As the pouches float, the fluid is exposed to the adsorbent thereby allowing contaminants to be removed from the fluid. When fluid completely fills the filter body, the fluid flows over the dam and into the drainage system.
One feature of the present invention is the ability to easily remove the filter body, the adsorbent pouch, or both, from the inlet. This provides the advantage of easily servicing the filtration system by removing the filter body or adsorbent pouches for cleaning or replacement.
In another embodiment, the catch basin filtration system is adapted to accommodate increased fluid-flow capacities. This embodiment provides increased filtered and bypass flow capacities, a substantially maintained shape of the fluid retaining reservoir, a means to retain floatables during periods of high flow, an adjustable supporting structure, and more readily maintainable components having longer periods of effective operation. This high capacity embodiment comprises a filter body defining a reservoir that is situated within a support basket having large apertures through its walls. This support basket may comprise a netting or geogrid, and is attached to and suspended from a support frame. Support cables combine with the support basket and an adjustable frame to form a filter body support. The filter body is connected to and substantially lines the walls and floor of the support basket. The filter body and frame are spaced apart and serve as an adjustable high flow bypass. Adsorbent containers in the form of elongated booms are removably suspended from the filter body walls in strategic configurations. A debris trap capable of retaining floatables and large debris during periods of high flow extends into the filtration system and rests atop the frame. In addition, stiffening and flow diverting baffles are attached or sewn into the filter body walls to assist in retaining floatables and large debris as well as to provide support to the filter body.
One feature of the present invention is the ability to accommodate basin openings of various dimensions. In a particularly preferred embodiment, various sizes of the support frame, which comprises a rigid inner support ring, support flanges and closure flanges, are employed to accommodate openings of various sizes. For example, the inner support ring can be of any pre-determined size. The size of the accompanying support basket, filter body and adsorbent pouches are dimensioned according to the inner support ring. The flanges come in pieces or sections, and can be easily assembled to attach to the inner support ring. Another feature of the present invention is a support system that permits a larger volume of fluid to be retained and processed by the system. In particularly preferred embodiment, support cables traverse the corners and cross the bottom of the support basket and function to hold the basket corners together, as well as to substantially prevent the support basket from bulging or expanding under the load imposed by the fluid and sediment held in the filter body.
Another feature of this embodiment is the adjustable high flow bypass, which exists at exposed large apertures of the support basket that are above the upper edge of the filter body and below the lower edge of the support frame. The walls of the filter body are held in place against the walls of the support basket, and the placement level of the upper edge of the filter body against the support basket may be raised or lowered, thereby respectively raising or lowering the high flow bypass capacity. Adsorbent booms are suspended within the filter body such that these booms float or otherwise become displaced as the filter body fills with fluid, which prevents the buildup of silt or sedimentation on the booms.